The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
An internal combustion engine in a hybrid powertrain is required to promptly start when determined by a control algorithm and based on operating conditions of the vehicle. High low-end torque is required to initially turn and accelerate the crankshaft to an acceptable speed before combustion. The initial high low-end torque is largely attributable to cylinder compression torque when intake manifold pressure is high and trapped air mass within the cylinders is high. One conventional approach to starting an internal combustion engine in a hybrid powertrain is accomplished by using the electric machine to accelerate the crankshaft of the engine to a speed at which combustion is initiated. However, in situations where the electric machine is multi-tasking, such as driving the vehicle with a large portion of full motor torque and starting the engine at the same time, this approach is complicated.